Mattress



The sole FIGURE is an isometric view of a front, top, and right side of an ornamental design for a mattress.

It is understood that the dash-dash-dash broken lines represent a pattern on the surface of the mattress or environmental structure that form no part of the claimed design. The dash-dot-dash broken lines on the mattress of the sole FIGURE depict a mattress with a symbolic break in its length and width. The appearance of any portion of the article between the break lines forms no part of the claimed design. 

CLAIM The ornamental design for a mattress, as shown and described. 